Plant mass thin, verdigris green. Filaments straight or nearly so, bluish-green, slightly or not at all constricted at the joints, either not at all attenuated towards the rounded and sometimes slightly thickened end or moderately tapering by two or three terminal cells. Cells 4-12 μm in diameter, 2-4 μm long, two to four times as wide as long, rarely nearly square. Dissepiments marked by a conspicuous row of granules on either side. Cell contents granular, pale blue-green or sometimes slightly brownish green.